Why is my screen going crazy with green/purple lines and flickering?

Ok, so I've had this laptop for about 3 years now. It's been working perfectly fine for the most, until my screen decided to start going crazy with colors and flickering. The screen every now and then starts flickering or it start displaying intense green or purple everywhere, but only in certain positions (angle between screen and laptop body). Also I've found a temporary fix, which is to apply pressure at the bottom part of the screen (I have a piece of cloth that I squeezed in between the laptop screen and the body, so that it applies pressure to the bottom part of the lcd)

So I've opened up the laptop to check if there wasn't anything loose or a cable that was badly connected and found nothing.

I've searched online quite a bit a found nothing either; I can't even determine what is causing this (GPU, LCD screen, cables...) so i can't even start thinking what i need to replace, or if it's even worth trying to repair.

If anyone could help would be greatly appreciated.